Turning point on Mars: Curiosity rover sets sights on mountain at last

The laser-equipped ChemCam instrument on NASA's Curiosity rover was used to check the composition of gray tailings from the hole drilled in a rock called Cumberland. This image, taken on May 21, shows a row of small pits created by firing the ChemCam's laser at the tailings. The pits are near the drill hole, which has a diameter of about 0.6 inch (1.6 centimeters).

After spending the past four months drilling holes in rocks on Mars, the team controlling NASA's Curiosity rover has set a course for the $2.5 billion mission's ultimate destination, a 3-mile-high (5-kilometer-high) mountain in the middle of the crater where Curiosity landed 10 months ago.

"We're going to hit the road and embark on a really new phase of the mission," Joy Crisp, the mission's deputy project scientist at NASA's Jet Propulsion Laboratory, said Wednesday during a teleconference with journalists.

Curiosity's managers selected Gale Crater specifically because of the mountain, known as Aeolis Mons or Mount Sharp. Its layers of rock are thought to preserve billions of years' worth of geological history. "It's like looking at the layers in Grand Canyon," Crisp explained.

A close examination of those layers could yield evidence of the chemical constituents of life. That's the top goal for the Mars Science Laboratory mission, which is slated to last two Earth years.

Valuable detourThe rover's current workplace, known as Glenelg, was actually a detour from the mountain trek, selected because orbital imagery suggested that it was an area of geological interest. That suggestion turned out to be right on: When Curiosity analyzed the powder that was drilled out of a rock nicknamed John Klein, researchers found that the material pointed to an ancient environment that would have been favorable for microbial life.

Over the next several weeks, the 1-ton mobile lab will take on three more tasks at Glenelg. First, it will study a strange rocky outcrop called Point Lake, which has the texture of Swiss cheese. The rock might be composed of volcanic lava, or it might be sedimentary in nature. "It's a nice mystery," Crisp said.

Curiosity will also take a close look at a layered outcrop called Shaler, which might have been a riverbed in ancient times. Along the way, it will use an instrument known as DAN, or Dynamic Albedo of Neutrons, to check for the signatures of ancient water at a boundary between areas of mudstone and sandstone.

In the meantime, mission managers will pore through orbital imagery for stopping points of scientific interest on the 5-mile (8-kilometer) route from Glenelg to Mount Sharp. So far, the rover has put just 2,405 feet (733 meters) on its odometer, so the trek to Mount Sharp will be monumental. "Somewhere between 10 months and a year might be something like a fast pace" for the trip, said Jim Erickson, the mission's project manager.

Crisp said she and the team's other scientists were anxious to get started. "It's like being on a vacation, and you spend a lot of time in a little area, and you've done a lot there — and you want a change of pace," she said.

That 'Mars rat'During the trip, Curiosity will no doubt pass by roadside attractions like the "Mars rat" that made such a splash over the past week. Crisp said the ratlike shape was created through wind erosion, mechanical abrasion and chemical weathering.

"In all honesty, I think that the scientists get so much more engrossed in the interesting textures and trying to figure out how the rocks form, that we're amused when people point out that this shape happens to look like something else," she said. "But we don't spend a lot of time thinking about why that is."

Crisp indicated that she didn't mind the hubbub over strange shapes. "It's kind of fun, in a way ... in that it will attract a lot of the public to look at the images, and learn a little bit about Mars," she said.